Change Alley

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Yet Another Hidden Cost Of Ethanol

with 10 comments

Folks in North America have woken up to the fact that gung-ho enthusiasm for converting the petroleum economy to ethanol has serious environmental and resource implications. We’ve been hearing for a while about the rising cost of food caused by switching to growing biomass crops. Here’s the latest bad news: water.

In Minnesota, one of the few states that require reporting of water use, a 2005 state study found that ethanol plants used an average of 4.5 gallons of water to produce 1 gallon of ethanol.

A proposed $165m ethanol plant in south-west Missouri will draw 1.3 million gallons of water from local aquifers every day. It will also generate 400,000 gallons of contaminated water per day — water that would be sprayed on land around the plant by irrigation equipment and then seep back into the ground.

St Louis Post-Despatch

A 100 million gallon-per-year ethanol plant is just one of many that have been proposed in the past few months across Illinois, which already has seven operating plants and is the nation’s No. 2 ethanol producer after Iowa. High oil prices and support from Washington have inspired such interest in ethanol that the Illinois Corn Growers Association now says at least 30 plants are in various stages of planning across the state. This proposed plant alone is estimated to require 300 million gallons per year, leading to pressure on aquifers and lowered well levels.

And don’t forget that even the most efficient methods of ethanol production yield only 1.3 units of energy for each unit of energy put into the system to make it. Read the figures carefully, as some companies conveniently forget to factor in the energy used by farmers in growing the raw materials.

Can someone remind me why this seemed such a good idea?


Written by Pete Smith

April 22, 2007 at 9:14 am

10 Responses

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  1. The phrase ‘running to stand still’ comes to mind regards biofuels.


    April 22, 2007 at 1:23 pm

  2. If people did a bit more running and a bit more standing still, perhaps we wouldn’t need to worry about petrol substitutes.

    Pete Smith

    April 22, 2007 at 1:25 pm

  3. Ha! Yes indeed. The world is certified insane.


    April 22, 2007 at 1:52 pm

  4. Just read in the Sunday Times that there’s a huge R&D drive going on in the US to look into refining biofuels for airplane use. Headed up by Boeing and involving Virgin and many large oil companies, they hope to have a fuel in use within 5 years. There’s aspirations to blend in up to 40% biofuel.

    It just gets crazier & crazier.


    April 22, 2007 at 3:57 pm

  5. The actual net energy value (USDA) is 1.06. The 1.34 and/or 1.67 values claimed are produced by taking an inferred “energy credit” for a non-energy coproduct, a livestock feed supplement.

    The logic of consuming large quantities of petroleum, LPG, and NG to produce more steaks and pork chops is left undefined.

    Even the net energy value does not deal with the fact that net energy production would be ~1/17th the gross production. When this is considered, corn ethanol could not meet more than 1% of U.S. gasoline energy consumption, even if all corn acreage were converted to such usage.

    The bioethanol industry is driven by the subsidy, not energy or environmental considerations.

    Russ Brown

    April 22, 2007 at 5:00 pm

  6. Hi all,

    That water used to ethanol ratio is actually pretty good. When I make wine, including water used for cleaning in the process, I use at least three times as much H2O. Economies of scale, I suppose.

    As to the surge toward bio-fuels, that’s all politics aimed at keeping our impatient culture interested, and willing to provide funding, until the research which should have come first gives us the technology to make it practical. As matt said, sort of, it’s a crazy world.

    the Grit

    the Grit

    April 23, 2007 at 7:50 pm

  7. Hi Grit,

    Your 3:1 water-ethanol ratio matches what I quoted in my original post for the proposed Illinois plant. Interesting that the historical figures from Minnesota indicate a 4.5:1 ratio, obviously techniques are improving.

    They’ve only just matched your winemaking performance though!


    Pete Smith

    April 23, 2007 at 8:14 pm

  8. Hi Pete,

    Sorry I wasn’t clear. I get more like a 15:1 ratio. I have access to some of the best brewing yeast, as my friend down the road runs a winery, and the highest alcohol level I can get is around 12%, so that should give you an idea. This makes that 4.5:1 a real accomplishment. Of course, I’m counting water used to clean the fruit and all the equipment, which may not be as exacting a requirement for ethanol production, as for something where flavor counts 😉 Still, with so much interest in the process, the yeasts will get better, meaning they will survive higher and higher alcohol levels, and as they do, my wine will pack that much more punch!

    the Grit

    the Grit

    April 24, 2007 at 5:56 pm

  9. Hi Grit,

    Yes sorry, I was having yet another senior moment and misread your post. I thought you meant “three times as much H2O” as alcohol, not “three times as much H2O” as the ethanol producers.

    I guess the difference is explained by the fact that your final product is 12% ethanol , whereas the big guys are producing 100%. They manage this by distillation, which I’m guessing you don’t do 😎 I’m trying to visualise the process by scaling up my memories of school chemistry labs, so I’m probably wide of the mark, but my impression is that distillation doesn’t use too much water compared with the initial fermentation.

    Surely cleanliness is still important, regardless of flavour. If you don’t clean your pots and tubes out you’ll get a batch of vinegar.


    Pete Smith

    April 25, 2007 at 7:56 am

  10. BBC Four’s ‘Costing the Earth’ says it will be looking at doing a programme topic covering ‘whether biofuels really are an environmentally sound option’. Once Auntie is onto it we know this concern over biofuels is starting to hit the mainstream. Phew!


    April 27, 2007 at 6:43 am

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